This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A039671 #12 Apr 28 2021 23:16:58
%S A039671 1,1,3,8,21,53,130,310,724,1661,3757,8398,18588,40800,88918,192592,
%T A039671 414907,889631,1899554,4040864,8567342,18109698,38176280,80278798,
%U A039671 168432854,352658013,736977583,1537420460,3202035086,6658948608
%N A039671 Row sums up to the main diagonal of the "postage stamp" array (n,m >= 0) defined in A007059.
%F A039671 Conjecture: a(n) = Sum_{k=1..n} A126198(n,k), for n > 0. - _L. Edson Jeffery_, Nov 29 2013
%e A039671 a(0)=1, a(1)=0+1=1, a(2)=0+1+2=3, a(3)=0+1+3+4=8.
%t A039671 f[ n_, m_ ] := f[ n, m ]=Which[ n>0, Sum[ f[ n-i, m ], {i, 1, m} ], n<0, 0, n==0, 1 ] Table[ Sum[ f[ n, j ], {j, 0, n} ], {n, 0, 30} ]
%Y A039671 Cf. A007059.
%K A039671 easy,nonn
%O A039671 0,3
%A A039671 _Richard L. Ollerton_ and Eirwyn L. Ollerton